1. Field of the Invention
The present invention relates to an image forming apparatus equipped with a container in which toner is contained.
2. Description of the Related Art
An image forming apparatus of an electrophotographic system forms a toner image by developing an electrostatic latent image formed on a photosensitive member using developer (referred to as toner, hereafter) in a development device. Since the amount of toner that can be accumulated in the development device is limited, the toner is replenished to the development device from a container that is detachable to the main body of the image forming apparatus.
For example, there is proposed a container that is provided with a rotation portion that is rotated, a pump portion for changing internal pressure of a chamber to discharge toner from the chamber that accommodates the toner, and a converter that converts a rotating motion of the rotation portion into a reciprocating motion of the pump portion (see US 20120014713A1). This container discharges the toner in a chamber by making the pump portion expand and contract according to the rotation of the container. That is, the air that is sucked from a discharging port as the pump portion expands loosens the toner in the chamber, and then, the chamber becomes in a positive pressure state and the air in the chamber forces out the toner, which covers the discharging port, from the discharging port as the pump portion contracts.
Incidentally, if an image forming apparatus is provided with a dedicated detection means to detect mounting/dismounting of a container in order to determine whether the container is dismounted from the image forming apparatus, there is a problem that the cost of an image forming apparatus will increase.